Hdmi Device and Power-Saving Method for Immediately Switching Hdmi Ports

1. A power-saving method for switching High Definition Multimedia Interface (HDMI) ports on a sink device, the sink device having a first HDMI port initially being enabled for displaying and a second HDMI port being disabled for displaying, the method comprising: using, by a sink device, reference signals to locate a VSYNC active edge in each frame generated by a source device connected to the second HDMI port of the sink device; turning on, by the sink device, power to the second HDMI port during a power-on region corresponding to the VSYNC active edge in each frame and turning off the power otherwise; obtaining, by the sink device, information related to a high bandwidth digital content protection (HDCP) in the power-on region; displaying, by the sink device, a video data from the source device based on the HDCP information when enabling the second HDMI port connected to the source device.

2. The power-saving method of claim 1 , wherein the reference signals comprise at least two of a horizontal data enable signal, a vertical data enable signal, and a timing of pixel location.

3. The power-saving method of claim 2 , wherein the VSYNC active edge is located by detecting edges of the reference signals.

4. The power-saving method of claim 3 , wherein the detecting values of the reference signals comprises: detecting whether the edges of the reference signals changing from a first value to a second value.

5. The power-saving method of claim 4 , further comprising: synchronizing a first clock of the source device with a second clock of the sink device before the VSYNC signal is located by the reference signals.

6. The power-saving method of claim 4 , further comprising: obtaining the HDCP information in the power-on region after the VSYNC signal is located.

7. The power-saving method of claim 1 , wherein the HDCP information comprises AVMUTE control information and HDCP control information.

8. A High Definition Multimedia Interface (HDMI) device, comprising: an HDMI interface, comprising a plurality of HDMI ports, wherein the plurality of HDMI ports comprise at least a first HDMI port initially being enabled for displaying and a second HDMI port being disabled for displaying; a controller, coupled to the HDMI interface, wherein the controller uses references signals to locate a VSYNC active edge in each frame generated by a source device connected to the second HDMI port, turns on power to the second HDMI port during a power-on region corresponding to the VSYNC active edge in each frame and turns off power of the other regions in each frame, and obtains information related to a high bandwidth digital content protection (HDCP) from the power-on region; and a display device, coupled to the controller, wherein the display device displays video data from the source device based on the HDCP information when enabling the second HDMI port connected to the source device.

9. The HDMI device of claim 8 , wherein the reference signals comprise at least two of a horizontal data enable signal, a vertical data enable signal, and a timing of pixel location.

10. The HDMI device of claim 9 , wherein the controller locates the VSYNC active edge by detecting edges of the reference signals.

11. The HDMI device of claim 10 , wherein the controller detects whether the edges of the reference signals changing from a first value to a second value.

12. The HDMI device of claim 11 , wherein the controller synchronizes a first clock of the source device with a second clock of the sink device before the VSYNC signal is located by the reference signals.

13. The HDMI device of claim 11 , wherein the controller obtains the HDCP information in the power-on region after the VSYNC signal is located.

14. The HDMI device of claim 8 , wherein the HDCP information comprises AVMUTE control information and HDCP control information.